Skin detection using a multi-band near-infrared (NIR) camera and its application to face recognition and human occupancy detection in a vehicle is well documented. As shown in FIG. 5, the characteristic of human reflectance in the NIR range includes a drop from 1000 nm to 1450 nm, a small rise to 1650 nm, a drop to 1900 nm, and then remains relatively constant for a range of wavelengths. As such, the full extraction of skin reflectances in the image requires many wavelength bands. Simply adding an increased number of wavelength bands to the camera increases the cost of the imaging system.
Accordingly, what is needed is an infrared camera system designed to maximize the detection of skin in infrared images acquired over 3 or 4 filter bands thereby enabling a cost-effective solution to vehicle occupancy detection systems and applications.